Cooling means for motor compressor units



Feb. 2, 1954 c. o. HARRIS ETAL 2,667,763

COOLING MEANS FOR MOTOR COMPRESSOR UNITS Filed Sept. 29, 1950 2 Sheets-Sheet l q ,Z732/ 7z fans: (arlesfiuyarrz's 13; WM. mm l" JQWL $1 3707M 12/19 4, 42 20 0%,.

5 c. D. HARRIS ETAL 2,667,763

COOLING MEANS FOR MOTOR COMPRESSOR UNITS Filed Sept. 29, 1950 2- Sheets-Sheet 2 Y F/ 523. l 28 iii. :1 8 32 i 37 34 1 Patented Feb. 2, 1954 oOZiLING'MfiANsnOR MOTOR COMPRESSOR UNITS rProsek, and Gerald P. McNamara,- Evansville, ..'Ind., 'assignors to International Harvester Company; a' corporation of New Jersey iipplication'Septeniber 29, 1950, Serial N0.-137,546

' 6laims. (elite-117.7)

L1 "This invention ie1atseenera11 to 't'hea'rt of refrigeration and more particularly to "an "improved refrigerant system andrnotor 'compressor unit.

This invention applies to a' refrigerantfsystem in which the refrigerant is d rawn from the evaporator by a "motor compfessor unit, compressed and then passed through "a 3 condenser "to be cooled and"liqii'efied. "During this o'perati'on the *n otor-compressol" triagenerates considerable heat and; some means "must be provided to cool the unit. In 'inany systems an --electric fan is provided for circulating room air into some "with the "condenser and then ever the "Ynot orcompre'ssor unit in order tocbolbothfihe con- 'denser and motor-compressor iinit. *If this" fan 'could'be eliminated, the initial cost of the sys- 'tem would be decreased' and the system would 'o'pe'rate'moreefficiently with alower noise level.

One object of the present invention i toprovide a refrigerant system'inwhich the necessity for acooling fan is eliminated. H I Another object of thein'vention is'to providea motor-compressor unit witha cooling'coil' immersed in the lubricating oil throughwhichre- 'frigerant' is circulatedin order to cool the motor "and compressor.

"A further object of theinvention isto provide a refrigerator cabinet with 'a condenser coil mounted on a portion of thefcabinets outer wall so that the heat'from the refrigerant'within the condenser coilwill' be conducted to said'outer wall and dissipated to the 'air surrounding the cabinet. "A further object orthe invention is'to provide means'for heating the 'outer walls of a refrigerator cabinet above 'rooin'teniper'atnre in order to prevent the condensationofnioisture'from the air unto the outerwalls.

p 'A still further object to provide a refrigerant system with a'motorcolnpressor cooling coil connected between a pair ofcondens'ers. ,The compressed refrigerant flows through the first condenser where it ishpartially cooled and liquefied, then passes through thecooling coil where it is reheated and then flows throughthe second con ldenser where it is completely cooled and liquefied.

.F i h r iect en advan a e off iic r se invention will become apparentas the following jdes cription proceeds andthe features of novelty which characterizelthi invention will'be pointed out withparticularity in th cl ainis annexed to and forming a part of thisspecification. V Fbr a be r 'nde.r an iie fLP QPr s nFH vention, reference may be had to the accompanyingdrawings in which:

provide a finished app-earance -to the' cabinet.

J2 Fig. 1 is a perspective view'of a*refr-igerator cabinet, witha portion cntawayyenihodying-the present invention.

Fig. 2 lsa right endvie'w" ofthe' cabinet =01 Fig. l with the oondensi'n'gunit-housingremoved.

Fig. 3'is a diagrammatic view'ofthe refrigerant system with a portion'of'the-rnotorcompressor casing cut away.

Fig. 4 isa persp'ectiveview' of the cooling coil with the casing represented -'by'-'"clotted*1ines.

Referring to the *dra'vifingsflnuineral"i D "desighates generally a freezer chest 'or eabinetiiaving a decorative outer shell IPSecured to base 12. Spaced within outer shell "I t'is an inner -liner !3 having walls which form's 'food' storage "compartment I i. Insulatingmateriall5 is placed between the outens'hell ll' andinrier liner I3 in order to reduce heat loss to a minimum. A breaker strip member l6'bridgesacross the top edges of outershell lI-and innerliner' I3=inorder to A door ii is hinged'to out'er'shell' H which closes and seals around thefood storage-"compartment it. A condensing" unit hou'sing" l8 isremovably secured to base it} and a motor-compressor unit 59 and a static condenser Zita-re secured to base it; under housing i8. -A 'gril le *2l is provided in the front wall of housing 18 through which conof outer shell ii "andaresecured in place *by clamps 25. I A

The motor-compressorhnit l9-"is provided with an upper casing 25' and alower casing 2? which are secured together in s ea'led relationship at 23. A compressor 29 disposeddnlowercasing 2'! and an electric rn'otortflfor driving the compressor is positioned in upper casing 26. Details of the motortfl and compressor 29 are not shown since they are not-important to the invention. v v V p In sealed motor-compressor'nnits'of'this type, considerableheat is generated during the operation of the refrigeration system. In ordertoremove heat from the motor-compressor unit it so that it will operate more efliciently, the present invention provides a cooling coil 3| which is located in 'thejlower portionbffbottomleasing 21 3| is bent into an upper run 33, turn 34 and lower run 35. The run 33 and 35 are parallel and are circular shaped. The end portions 36 and 3! of runs 33 and 35 respectively extend through bottom casing 21 and are secured thereto by silver solder 38. The runs 33 and 35 are positioned between compressor 29 and bottom casing 21 and extend approximately three quarters of the Way around the compressor.

Slots 39 and 40 are provided in end wall 4| of the outer shell through which conduits pass to complete the refrigeration system. The compressor inlet 42 is connected to evaporator coil 22 by conduit 43 and the compressor outlet 44 is connected to the static condenser 20 by conduit 45. Conduit 46 connects the end portion 31 of lower run 35 of the compressor cooling coil 3| to static condenser 20 and conduit 41 connects the end portion 36 of upper run 33 to the condenser coil 24. The condenser coil 24 and evaporator coil 22 are connected by a restrictor tube as.

During the operation of the refrigeration system, the compressor draws refrigerant vapors from the evaporator coil 22 through conduit 43, compresses the vapors and then forwards the compressed refrigerant through conduit 45 to the static condenser 23. As the compressed refrigerant flows through the static condenser 23, it will lose some heat to the air surrounding the condenser and be partially condensed. From condenser 20 the refrigerant flows through conduit A6 to the cooling coil 3| where it absorbs heat from the hot lubricating oil 32 and again returns to the vapor state. Since the lubricating oil 32 is circulated into contact with the compressor 29 and electric motor 33, it will pick up considerable heat while the refrigeration system is operating. As this heated oil comes into contact wtih cooling coil 3|, it will be cooled and the operating temperature of the motor-compressor unit i9 will be lowered substantially.

The refrigerant is carried from cooling coil 3| by conduit 4'! to condenser coil 24 where heat is conducted from the refrigerant to the outer shell H and then dissipated into the air surrounding the cabinet. 7 The refrigerant will be cooled and condensed and the outer shell M will be heated a few degrees above room temperature. In refrigerator cabinets of the type described, some heat leakage will occur between the inner liner |3 and outer shell H which causes the temperature of the outer shell to be lowered below room temperature. As the room air strikes this cool surface, moisture will condense from the air onto the outer shell. This is very undesirable since the condensate is harmful to the finish of the outer shell and will eventually drip onto the room floor. In the present invention, no condensate will collect on outer shell since it is heated to a temperature slightly higher than the room temperature by condenser coil 24.

From the condenser coil 24 the refrigerant is metered by restrictor tube 43 into the evaporator coil 22 where it absorbs heat from the inner liner l3 and is vaporized. The temperature of the inner liner I3 is reduced suiiiciently to cool the food compartment l4 to the desired temperature. From the evaporator coil 22 the refrigerant returns to the motor-compressor unit l9 through conduit 43.

While there has been shown and described a particular embodiment of this invention, it will be understood that various modifications and changes will occur to those skilled in the art. The disclosure is illustrative and the invention is to 2,667,768 e r R be limited only in accordance with the claims appended hereto.

What is claimed is:

1. In combination, a refrigeration system comprising series refrigerant circuit means operable to cause a refrigerant to absorb heat in one portion thereof and to emit heat in another portion thereof, a casing, a motor-compressor unit for operatin said series refrigerant circuit means disposed within said casing, an oil for lubricating and cooling said motor-compressor unit, an oil reservoir in the bottom portion of said casing and containing said oil, and a coil disposed in said oil reservoir in heat exchange relation with said oil, said coil having runs which extend around said compressor and end portions which extend through said casing and are secured thereto, said end portions being connected in series in said one portion of said series refrigerant circuit means wherein said refrigerant absorbs heat so that said refrigerant flows through the coil and absorbs heat from said oil.

2. In a refrigeration system, a casing which encloses a motor-compressor unit, an oil for lubricating and cooling said motor-compressor unit, an oil reservoir in the bottom portion of said casing containin said oil, said compressor extending into said oil reservoir, a cooling coil positioned in said oil reservoir having circular shaped turns which extend around said compressor and end portions which extend through said casing and are secured thereto, said turns spaced between said compressor and said casing, a heat exchange unit connected in said refrigeration system and to said coil, and a refrigerant in said system which is cooled by said heat exchange unit and then passed through said coil Where it absorbs heat from said oil from the motor-compressor unit.

3. In a refrigeration system, an evaporator, a motor-compressor unit, a pair of condensers, a casing which encloses said motor-compressor unit, a reservoir provided in the bottom portion of said casing for collecting lubricating oil, and a coil disposed in said oil reservoir having circular shaped turns which extend around said compressor and end portions which extend through said casing and are secured thereto, said end portions being connected between said condensers, means connecting said motor-compressor unit and said evaporator to said condensers so that said motorcompressor unit is operable to deliver refrigerant to one of said condensers, through said coil, through the other of said condensers, through said evaporator, and to draw refrigerant from said evaporator when said system is charged with a refrigerant, said one condenser formed to operate to pre-cool said refrigerant delivered thereto, said pre-cooled refrigerant delivered through said coil operating to draw heat from said oil, and said other condenser formed to operate to cool said refrigerant delivered therethrough.

4. In a refrigerator cabinet, an evaporator, a motor-compressor unit for drawing refrigerant vapors from said evaporator and compressing the same, a first condenser for partially cooling the refrigerant, a second condenser for completely cooling and liquefying the refrigerant, said second condenser disposed in heat exchange relation with the outer walls of said cabinet, a, casing for enclosing said motor-compressor unit which has a reservoir for lubricating oil, and means for cooling the motor-compressor unit, said means including a cooling coil disposed in said reservoir in heat exchange relation with the lubricating oil,

said cooling coil being connected between said condensers so that the refrigerant will flow therethrough.

5. In a refrigerator cabinet, an evaporator, a motor-compressor unit for drawing refrigerant vapors from said evaporator and compressing the same, a first condenser for partially cooling the refrigerant, a second condenser for completely cooling and liquefying the refrigerant, said second condenser disposed in heat exchange relation with the outer walls of said cabinet, a casing for enclosing said motor-compressor unit which has a reservoir for lubricating oil, said compressor extending into said reservoir, and a coil disposed in said oil reservoir having runs which extend around said compressor below the surface of the oil and two end portions which extend through said casing, said first condenser being connected to one end portion and said second condenser being connected to the other end portion so that refrigerant will flow through said coil and absorb heat from said oil.

6. In a refrigeration system, a casing which encloses a motor-compressor unit, an oil for lubricating said motor-compressor unit, an oil reservoir provided in said casing, a first condenser for partially cooling refrigerant within said system,

1 "a second condenser for completely cooling the re- Jfrigerant, and a cooling coil disposed in said oil reservoir in contact with said oil, said coil being connected between said condensers so that the partially cooled refrigerant flowingitherethrough "from said first condenser will absorb heat from said oil.

- CHARLES D. HARRIS.

ROBERT L. EICHHORN. JOHN R. PROSEK. GERALD P. McNAMARA.

V v References Cited in the file of this patent UNITED STATES PATENTS 

